Dry Autopsies

Dry autopsies came into practice relatively recently, in the 1990s. Professor 0ye implemented them in the analysis of failure modes [10]. Although rather costly, diy autopsies are a good instrument for understanding cathode failure reasons in order to make corrective actions in the construction of the cell, to pay special attention to the quality of lining materials, or to make corrective actions to the preheating and startup procedures. In our days a series of dry autopsies (with different service time of the cell) is a standard procedure in the process of the design and implementatiOTi of the new cell type. 

Usually, the analysis of the reasons for shutdown of the cell, based on the dry autopsy results, is state-of-the-art, but a very brief description (mainly from Prof. 0ye [10]) may help to remember the necessary actions during the process. 

Make a dry autopsy plan (the full process is time-consuming and may take up to 2-3 weeks), which includes the collection of all initial information on the cell, the dry autopsy process itself (which may take a long time), analysis of the lining materials received in the course of the dry autopsy, the preliminary report and the final report of results of the autopsy, and the causes of the failure (if there s a failure) (Fig. 2.15). 

Collect all preliminary information (cell design, lining design, lining material specifications, information on producers, information on shell, type of preheating 

Measure the geometry of the shell (length, width, diagonals) and compare it with the drawing (deformations of the sides, of the bottom) and inspect possible cracks and local deformations of the shell, steel bars, and steel bar windows. 

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Fig. 1.12 Cathode bottom of reduction cell before the dry autopsy...

Fig. 2.10 (a, b) Shapes of cracks in carbon cathode block due to thermal tensions at casting (c) picture of cracks in block at dry autopsy... 

Fig. 2.15 Plan view (a) of reduction cell, cleaned from electrolyte and aluminium for dry autopsy. 1— visual cracks in cathode blocks, 2— planned places for trenches (b) cross section of the lining from the trench 1—crack in cathode block with traces of aluminium 2—aluminium under the crack 3—corroded by electrolyte refractory (c) photo of dry autopsy...

The ratio of the surface of a peripheral seam, filled in with ramming paste, to the surface of the cathode (if combiblocks are not the part of the construction) is 1.5-2.5 %. At startup, usually the temperature of the peripheral seam is low and sufficiently lower than the freezing point of electrolyte. Even in normal operation, the temperature of the peripheral seam is not high, and usually it is covered against penetration of electrolyte with a side ledge. However, sometimes [41] during dry autopsies, the peripheral seams are fully infiltrated with electrolyte, and so it is worth controlling the pore size distribution. 

Fig. 2.80 The cell with bottom heaving before dry autopsy...

Fig. 2.87 Picture of dry autopsy due to pressure and the formation of the lens, the height of the heat insulation layer decreased...

Lining of Reduction Cells. The Preheating, Startup, and Operation. Retrofit of Cells and Tendencies. The Main Causes of Failures. Dry Autopsies... 

Dry autopsy a complex set of actions to investigate the reasons for shutdown of the cell. This includes investigating the surface of the cell, cleaned of electrolyte and aluminium, digging trenches in the lining in chosen parts of the cell, and examining the condition of the lining and the lining materials. 

For postmortem analysis, blood and bile are collected at the latest at the time of autopsy. Otherwise, as is true for plasma samples, the most informative results are obtained when blood samples are collected during acute illness or at least prior to a meal (see 3.2.4, subheading Specimen ). Blood should be obtained by capillary stick of well-perfused skin (heels in young infants or fingers) and free dripping of a few drops of blood directly on the filter paper card. Following complete drying at room temperature for at least 3 h, the sample can be sent ambient. Analysis should be... 

Radionuclide Analyses of Human Liver. Several specimens (12) of human liver obtained at autopsy were prepared similarly, except that after they were freeze-dried they were ball-milled to insure homogeneity of radionuclide distribution in the counting sample. The powdered samples were then compressed into aluminum cans and counted for approximately 2000 minutes. 

Chace DH, DiPerna JC, Mitchell BL, Sgroi B, Hofman LF, Naylor EW. Electrospray tandem mass spectrometry for analysis of acylcarnitines in dried postmortem blood specimens collected at autopsy from infants with unexplained cause of death. Clin Chem 2001 47 1166-82. 

Bone samples for aluminium analysis have been taken from the iliac crest at the time of biopsy or at autopsy (Alfrey et al.. 1976 Maloney et al., 1982) and the specimen placed in an Al-free plastic container. Bone for histological staining is fixed in 10% buffered formalin (Maloney et al., 1982). Crapper et al. (1976) analyzed brain samples from specific areas of the cerebral cortex and from subcortical area. Alfrey et al. (1976) analyzed brain samples from frontal cortex. Whole brain as well as white and grey matter were analyzed. A description of how the specimen was handled before analysis was not provided. Crapper et al. (1976) transported and stored brain samples frozen in Al-free plastic containers and performed dissection from the frozen specimen in a dust-controlled room. All instruments and gloves were rinsed in aluminium-free water. At frequent intervals, this entire procedure was performed on standard homogenized freeze-dried brain powder to ensure little or negligible aluminium contamination. 

Arsenic was determined in freeze-dried samples of human autopsy tissue (Aalbers et al., 1987) by gamma-counting following appropriate irradiation and absorption on an ion exchanger after a semiautomated separation procedure together with radionuclides from Se, Sb, and Hg (Tjioe et al, 1977). Arsenic contents as low as 1 / g/kg (dry weight) were easily determined. 

Sexually naive juvenile (24—28 days of age) and mature (60—70 days of age) females were tested. Females were randomly assigned to one of three treatments within each age class control (N = 10 juvenile and 11 mature females), male urine (N = 9 juvenile and 12 mature females), or presence of adult male (N = 9 juvenile and 10 mature females). Juvenile females received one drop (approximately 0.3 ml) of urine or saline on the nasal phil-trum daily for seven days, beginning the day after removal from their home cage. Mature females were treated the same as juveniles except that treatment began when they were 60-70 days of age. Females were euthanized using an intraperitoneal injection of pentobarbital on the eighth day after treatments started. Body mass of females was recorded prior to autopsy. Uteri were cleaned of fat and connective tissue and the cervix was removed. Uteri were blotted dry and then weighed to the nearest 0.1 mg. 

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